Technical Field
The present disclosure relates to a vehicle, particularly to a vehicle including a combustion engine.
Description of the Background Art
Japanese Patent Laying-Open No. 2001-159359 discloses a fuel pressure control device of an engine. This fuel pressure control device performs a feedback control so as to control an actual fuel pressure of fuel supplied to an engine to match a target fuel pressure. This fuel pressure control device can variably set a control gain at the time of performing the feedback control. Specifically, provided are a first control gain used in the case where the fuel pressure is in a steady state and a second control gain used in the case where a change in the fuel pressure is great. The second control gain is less than the first control gain. This fuel pressure control device switches the control gain from the first control gain to the second control gain when the target fuel pressure is changed by a predetermined amount or greater.
Accordingly, overshoot and undershoot in the fuel pressure during fuel pressure transition are suppressed, and a difference between the actual fuel pressure and the target fuel pressure is converged assuredly.
In the fuel pressure control device disclosed in Japanese Patent Laying-Open No. 2001-159359, the target fuel pressure of fuel supplied to an engine is determined in accordance with an operational state of the engine. It can be contemplated that the target fuel pressure is lowered in accordance with the operational state of the engine. When the target fuel pressure is lowered, and if the temperature of the fuel is high, fuel is vaporized (generates vapor) in fuel piping. When vapor is generated in fuel piping, a quantity of fuel injected to the engine becomes insufficient as compared to a target amount.
On the other hand, if it is attempted to maintain a high target fuel pressure regardless of the operational state of the engine, it would be necessary to supply great electric power to a pump which applies a pressure to fuel. This is not preferable in view of fuel consumption.